TESTUDINIDAE 361 



way, used in the salt marshes, is for the negroes to go tramping 

 through the mud and water. If they pass any terrapin these 

 will rise out of the mud to see what the disturbance is. The 

 captives are then fattened in the " crawl." When the men go 

 in to feed them they whistle, and terrapin from all over the 

 "crawl," thousands of them, come swimming through the water, 

 piling over each other in their efforts to get close to the man 

 with the shrimps and crabs. 



Cistudo. The plastron, without forming a bridge, is connected 

 with the carapace by ligaments, and is divided into two movable 

 lobes, the transverse hinge being so perfect that the box can be 

 completely closed after head, legs, and tail have been withdrawn. 

 The nuchal shield is very small ; the first four neurals are large 

 and broad, the fifth much broader than long. There are twelve 

 pairs of marginal shields. The carapace is high and arched. 

 The digits are almost completely free. The tail is very short. 

 The skull is without a bony temporal arch, the quadrato-jugal 

 and the .jugal being absent. Only two species, in North 

 America. 



C. Carolina of the Eastern United States is a very interesting 

 species. Closely allied by its internal structure to the water- 

 tortoises, it has become absolutely terrestrial ; and the shape of 

 the head, the convex shell which is coloured black and yellow or 

 orange-brown, and the short webless fingers are all terrestrial 

 features. But the rather long toes, provided with long and sharp 

 claws, the broad and flat feet, enlarged by a broad fold of skin on 

 the outer margin, the long oval eggs, the smooth covering of the 

 head, and the preponderant animal diet, still proclaim the aquatic 

 relationship of this tortoise. It is in fact a genus which has 

 changed habits and features from aquatic to terrestrial life. The 

 head is covered with a smooth skin, and the upper beak, especially 

 in old specimens, is strongly and broadly hooked. The eyes of 

 the males are red, those of the females are brown. The plastron 

 of the males is concave, that of the females is flat. Large 

 females reach a length of nearly six inches. The young are 

 nearly round, with high, arched back and prominent keels. The 

 keels of the middle line remain a long time, but they gradually 

 flatten down with age, being prominent only at their posterior 

 ends. Each dorsal shield is originally nicely sculptured, with 

 a well-marked areola and concentric rings. Very old individuals 



